What is light composed of? I know that when an excited electron moves back down to a lower energy level, it releases a photon of light...

but what is that photon of light composed of? Everything must be composed of something...or maybe it is the absence of something...etc....

10-16-2001

Unregistered

my favorite quote from enstein himself

"He who thinks he understands quatum mechanics does not."

10-16-2001

rick barclay

Quote:

Originally posted by adrianxw Yes, I'm well aware of the external funding. My point really is that .5 UKP is little more than the price of a postage stamp here, and as you also point out, the science is made available.

Consider the amounts of public money that the US puts into places like Brookhaven and Sandia, and much of that work is never made public.

I maintain that CERN is not an excessive demand on the member governments in the way that rick, with his talk of food and football, would like to believe.

Ok, Ok. Cool your roll, Adrian. You can argue with the other
blokes who actually have to dish up half a pound so you can
play with your toys. I'm sure it's all worth it.

I've posted the Feynman Lecture's on Physics in five zipped
files at flashdaddee.com. There are a total of, I think 34
chapters and an index. If more become available, I'll let
everyone know. Hope you all enjoy them.

rick barclay

10-17-2001

adrianxw

DavidP:

>>> What is light composed of?

As you rightly say, photons. A photon is a boson. If you think about it, when an excited atom reverts to a lower energy state, it emits a photon, this photon can be absorbed by another atom thus promoting it to the excited state. This is exactly the idea of bosons. The force is transferred from one place to another by a force carrying "particle", in this case a photon. The weak nuclear force is mediated by w+, w- and z0 bosons, the strong nuclear force by a flock of gluons, for which there is some direct evidence.

Gravity is, at the moment at least, the odd one out. The model has been extended to contain the "Graviton" but there is no evidence for it, and it remains hypothetical. Many theories at present predict, for example, gravity waves, (pulses of gravity), from big cosmic events. A few experiments are in the pipeline now based on very acurately aligned lasers running at right angles to each other, and trying to detect distortions which a passing gravity wave would cause. It's early days yet. A more ambitious scheme is to set up a space based system along similar lines but with enormously longer "legs" thus renderind it far more sensitive, but this is a good few years away.

rick barclay:

Whatever you say.

10-17-2001

Procyon

Quote:

Originally posted by adrianxw Many theories at present predict, for example, gravity waves, (pulses of gravity), from big cosmic events. A few experiments are in the pipeline now based on very acurately aligned lasers running at right angles to each other, and trying to detect distortions which a passing gravity wave would cause. It's early days yet. A more ambitious scheme is to set up a space based system along similar lines but with enormously longer "legs" thus renderind it far more sensitive, but this is a good few years away.

If anyone's interested, information on these two projects can be found at